1. Field of the Invention
The present invention relates to a solar power generation system, by which DC power generated in a solar cell can be utilized efficiently and a high AC output voltage can be set.
2. Description of the Background Art
Recently, attention has been given to a solar power generation system that is interconnected with a system power supply, which is a commercial AC power supply system, by converting the DC power obtained from a solar cell into AC power. This solar power generation system is generally constituted by an inverter which converts the DC power obtained from a solar cell group comprising a plurality of solar cells into AC power of a predetermined frequency, and a transformer which supplies the AC power output by the inverter, to the system power supply.
The power obtained from the solar cells varies depending the intrinsic differences of the individual solar cells. Therefore, differences are certain to occur naturally in the power obtained from each of the plurality of solar cell groups, which are formed by grouping together a plurality of solar cells. Therefore, it has been proposed to make the voltages input to the inverter equal to each other by forming a plurality of solar cell groups by connecting solar cells which have similar output voltages together in parallel, and providing voltage adjustment means for each of these solar cell groups (see, for example, Patent Document 1).
Furthermore, in the abovementioned solar power generation system, the operating point of each solar cell group is controlled by controlling the output current of the inverter, for example, whereby the DC power obtained from the solar cell group is maximized. The control of the operating point of the solar cell group is called “maximum power point tracking” (MPPT) control.
Patent Document 1: Japanese Patent Application Publication No. 2001-309560